He becomes the first to throw a postseason no-hitter since Don Larsen's perfect game for the Yankees in the 1956 World Series. Halladay threw a perfect game against Florida in May.

Reporting from Philadelphia — Philadelphia Phillies pitcher Ryan Madson said it was the most nervous he has been during a baseball game. And he was sitting in the bullpen.

Bench coach Pete Mackanin, who was standing in the dugout, said it was obvious he was watching history by the fifth inning of Roy Halladay's postseason debut Wednesday.

"There was no doubt," he said. "You didn't want to think it. But you had to."

And catcher Carlos Ruiz said he knew even earlier. When he got to the ballpark, more than five hours before the game with the Cincinnati Reds, Ruiz sensed something special was about to happen.

When he began warming up with Halladay, that feeling grew stronger.

"I just said, 'Oh my God. He's on today,' " Ruiz said.

Was he ever. After waiting a dozen big league seasons for his first playoff start, Halladay made sure it was a game worth waiting for, dominating the Reds while throwing the first postseason no-hitter in more than half a century in a 4-0 win.

"It's surreal, it really is," Halladay said. "I just wanted to pitch here, to pitch in the postseason. To go out and have a game like that, it's a dream come true."

Even in their dreams, few pitchers are as masterful as Halladay was Wednesday. Facing a powerhouse lineup that led the National League in virtually every significant offensive category during the regular season, the right-hander retired the first 14 Reds before walking Jay Bruce with two outs in the fifth inning on a sinker that Ruiz said didn't move enough.

"It was close," he said.

That would prove to be all Cincinnati would get, though, as Halladay came within a pitch of his second perfect game of the season.

As it was, Halladay's gem was the second postseason no-hitter, joining Don Larsen's perfect game for the New York Yankees in the 1956 World Series. And he made it look easy, throwing first-pitch strikes to 25 of the 28 batters he faced and going to three-ball counts only three times.

Of the 104 pitches he threw, 79 were strikes. And in the eighth inning, when he should have been getting tired, he retired the side on seven pitches, striking out two batters.

"It's just one of those special things I think you'll always remember," said Halladay, who found a bottle of champagne resting in ice next to his locker when he returned to the clubhouse. "But the best part about it is the playoffs take priority, and that's pretty neat for me to be able to go out and win a game like that and know there's more to come for us and more to accomplish."

It's unlikely there will be many accomplishments that will top Wednesday's. When Halladay took the mound for the ninth inning, he was greeted by a standing ovation from the towel-waving crowd of 46,411, which stayed on its feet, growing louder by the pitch until Halladay retired Brandon Phillips on a tapper in front of the plate for the final out.

"I've been in baseball 50 years, this is the first time I've seen a guy throw two no-hitters in a year," said Manager Charlie Manuel, who saw Halladay throw a perfect game against the Florida Marlins in May. "Absolutely unreal."

Cincinnati Manager Dusty Baker agreed.

"That is the best-pitched game I've seen since I've been going to the playoffs and World Series," said Baker, who played in four playoff series and three World Series and managed in the postseason four times. "It was like a situation where you're almost helpless because the guy was dealing. That was great pitching tonight."

Halladay struck out eight batters and was in such control that his defense was called on to make only two plays that weren't routine -- a sliding catch by right fielder Jayson Werth to end the third inning and a grounder that took a tricky hop off the mound to shortstop Jimmy Rollins, who stayed with it to get the second out in the sixth.

Ruiz also had a tricky play for the final out when the ball Phillips hit in front of the plate came to rest against his bat. But Ruiz collected the ball, avoided the bat and, from his knees, made the throw to first base in plenty of time.

"Everything was working today," said Ruiz, who said Halladay shook off his pitch selections once, in the final inning. "So we threw anything on any count."

Lost in the shuffle was Halladay's run-scoring single in the second inning. He came around to score Philadelphia's final run and afterward he was all smiles, which is rarer for Halladay than throwing a no-hitter.